* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.container {
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    max-width: 600px;
    width: 100%;
    overflow: hidden;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px 30px;
    text-align: center;
}

header h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
}

header p {
    opacity: 0.9;
    font-size: 1.1em;
}

main {
    padding: 40px 30px;
}

.drop-zone {
    border: 3px dashed #ddd;
    border-radius: 15px;
    padding: 60px 40px;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
    margin-bottom: 30px;
}

.drop-zone:hover {
    border-color: #667eea;
    background-color: #f8f9ff;
}

.drop-zone.dragover {
    border-color: #667eea;
    background-color: #f0f2ff;
    transform: scale(1.02);
}

.drop-zone i {
    font-size: 4em;
    color: #667eea;
    margin-bottom: 20px;
}

.drop-zone h3 {
    color: #333;
    margin-bottom: 10px;
    font-size: 1.5em;
}

.drop-zone p {
    color: #666;
}

.file-list {
    margin-bottom: 30px;
}

.file-list h3 {
    margin-bottom: 20px;
    color: #333;
    font-size: 1.3em;
}

.file-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 10px;
    margin-bottom: 10px;
}

.file-info {
    flex: 1;
}

.file-name {
    font-weight: bold;
    color: #333;
    margin-bottom: 5px;
}

.file-size {
    color: #666;
    font-size: 0.9em;
}

.progress-bar {
    width: 100%;
    height: 6px;
    background: #e9ecef;
    border-radius: 3px;
    overflow: hidden;
    margin-top: 8px;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #667eea, #764ba2);
    transition: width 0.3s ease;
    border-radius: 3px;
}

.status {
    font-size: 0.9em;
    margin-left: 15px;
}

.status.converting {
    color: #667eea;
}

.status.success {
    color: #28a745;
}

.status.error {
    color: #dc3545;
}

.actions {
    display: flex;
    gap: 15px;
    justify-content: center;
}

.btn {
    padding: 12px 30px;
    border: none;
    border-radius: 8px;
    font-size: 1em;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.btn-secondary {
    background: #6c757d;
    color: white;
}

.btn-secondary:hover {
    background: #5a6268;
}

footer {
    text-align: center;
    padding: 20px;
    color: #666;
    font-size: 0.9em;
    background: #f8f9fa;
}

@media (max-width: 768px) {
    .container {
        margin: 10px;
        border-radius: 15px;
    }
    
    header {
        padding: 30px 20px;
    }
    
    header h1 {
        font-size: 2em;
    }
    
    main {
        padding: 30px 20px;
    }
    
    .drop-zone {
        padding: 40px 20px;
    }
    
    .actions {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
}
